From the Richmond Sentinel, 5/25/1863, p. 2, c. 2

Shipped. – Six hundred and fifty-odd Yankee prisoners left the Libby prisoners
left the Libby prison on Saturday morning for City Point. They were in charge of
Lieut. La Touche. A Canadian, named Kirby, who for sometime has been confined in
Castle Thunder, under the suspicion of being a spy, was sent off with them.